A debonair (persona gallarda, o alegre) person is usually elegant in the way he dresses.
This is usually combined with a cheerful (alegre) and courteous (cortés) manner.
Examine these examples:
* Mrs. Thatcher, the British Prime Minister in the 1980s, was a debonair woman (…era una mujer cortés).
* The girl fell in love with a debonair young man (…se enamoré del joven gallardo).
So, are you debonair?